Electric fire pot



June 3 1924- W. S. HADAWAY. JR

ELECTRIC FIRE POT Filed March 24, 1922 A TTORNEY.

Patented June 3, 1924.

WHILIAI S. HADA'WAY', JR, NEW ROCHELLE, NEW YORK.

ntnc'rnrc rum ror.

Application fled larch 24, 1922. Serial Io. 548,387.

To all whom it may concern:

Be it known that I, WILLIAM S. HADAWAY Jr., acitizen of the UnitedStates, anda resident of New Rochelle. county of Westchester, and Stateof New York, have invented certain new and useful Improvements inElectric Fire Pots, of which the followin is a specification.

%his invention relates to improvements in W electric fire pots and moreparticularly to apparatus such as is used for the melting or heattreatment of metals, or for other purposes requiring very hightemperatures. The invention has for its main object the improvement ofmeans for the generation of high temperatures and the provision ofapparatus of higher efficiency that shall be applicable to a variety ofpurposes For example, the heat applicator of my inven- 29 tion may beused in connection with a melting crucible for the refining or treatmentof metal; in which case its heat is directed to the work by radiationand suitable reflection. Or it may be employed as an immersion type ofheater; in which case its heat is applied by conduction. Again. it maybe used as a central generator or furnace in a system of heatdistribution; in which case the heat is carried to the utilities 30 byconvection. The invention serves to intensify combustion in a chamberand effectually to control the rate of combustion.

Another object relates to means for employing as one active agent arelatively high cost medium in combination with a relatively low costmedium whereby the ciliciency of the high cost medium in producing heatis greatly increased resulting in a reduction of the proportional amountof the high cost medium.

Another object relates to the provision of electrodes of im rovedconstruction and the employment 0? a fuel in proximity thereto, wherebyhigh temperatures relative to the theoretical combustion temperature ofthe fuel may be obtained and utilized. According to this feature, amaterial such as magnesia, having predetermined characteristics at hightemperatures, is employed in the electrodes, whereby the formation ofcarbides in combination with the carbon contained in the fuel, which hasoccurred with electrodes of dprior construction, is effectually preventeAnother feature relates to the provision of an improved electric furnaceem loying a gas for initiating combustion an maintaining the temperatureof a burning fuel at or near its temperature of chemical combination,whereby an incandescent resistor of greatly increased length andtemperature 15 produced.

nother feature relates to a heat applicator in which an electric firepot is provided with active electric members or electrodes which arenon-combustible whereby tllieficgntrol and regulation of heat are simp 1e Still another feature relates to interchangeability of parts. wherebythe heat applicator may be readily and conveniently replaced in thecontainer in which it is employed.

Other objects will appear from the following description taken inconnection with the accompanying drawing, in which,

Fig. 1 shows a sectional elevation of a heat applicator of my invention.in position for heating the contents of a melting pot.

Fig. 2 shows an enlarged sectional view of a portion of the apparatus.

Fig. 3 shows a section taken on the line 3-3 of Fig. 2.

Fig. 4.- is a sectional view of a modified form of the invention shownin Fig. 3.

' Like characters of reference refer to like parts in the severalfigures of the drawing.

Referrin to the drawing. there is shown an illustrative embodiment ofthe invention, comprising a cylinder 15 of refractory material, havingits lower end closed and preferably rounded off to facilitate immersionthereof into viscous liquids. .The cylinder may be ridged or corrugatedin order to increase its active surface. The open up er end of thecylinder is closed by a detachable seal comprising a cover plate 17resting on an internal shoulder in the cylinder 15 and preferablysecured thereto in any suitable manner. The plate 17 is made of asuitable refractory material and is surmounted by a second plate 18 madeof a material which is an insulator of electricity and capable ofwithstanding a high degree of heat.

A urality of electrodes such as 20, 21 extend through slots in theplates 17, 18 the supports therefor being secured to the insulatin plate18, in any desired manner. Eac of these supports (Fig. 2) comprises ayoke or bridge'22 for pivotally supporting upon trunnion bearings therespective electrode and its carriage 23 (Fig. 3). Thus the electrodesmay be rocked or tilted. Each of the yokes 22 has an extension 24 withan upri ht toothed segment 25, and the corresponding electrode carriage23 has an arm 26 movable in proximity to the segment 25. The free end ofeach arm 26 is shaped in the form of a handle and suitable latchingmeans 27 may be provided for maintaining the electrode in a givenposition when desired. It is understood, how.-

- ever, that any suitable form of moving or maintaining means,automatic, manual or semi-automatic, may be employed for these pu ses.

e electrode supports and carriage are preferably made of nickel chromiumor other suitable material.

The electrodes 20, 21' are made of a fulgurite such as oxide ofmagnesia, which is a conductor of electricity only when hot. They aremade hollow in the form of tubes, the upper extremity of each beingprovided with a suitable binding post 30. Each elec trode is mounted orclamped on the carriage 23 in any suitable manner and a transversepassage .31 leads through the wall of the electrode, one flange of thecarriage member 23 and through a stufiing box 32, connecting to a supply33 for supplying a suitable gas or Vapor to the electrode. The bindingposts each may comprise a split collar 30 of electrically conductingmaterial fitted over the upper end of the respective electrode, andfastened by means of a suitable set screw. Leading from the electrodesis a corresponding plurality of conductors connected to a source ofcurrent 34:. The source current and as shown a single phase alternatingcurrent is supplied; it is understood,

however, that two or three phase current may be employed, the number ofconductors and electrodes being then increased to four and three eachrespectively.

The supply 33 isconnected to a main passage 35 leading to one of theelectrode supports for supplying active medium thereto. A by-passtherefrom (see Fig. 1) leads to one part of a valve 36. A second part ofthe valve is connected by means of a passage 37 to another of theelectrode supports, and serves to supply or to withdraw active mediumtherefrom depending upon the position of the valve 36. A third part ofthe valve 36 is connected by means of a passage 38 to the source 33.

The passage 38 may be extended'to utilities instead of to the source 33,and theproducts of combustion and unconsumed vapors may thereby beemployed to actuate such utilities. The utilities may take any desiredform, such as that of a hot plate of conventional design.

In the interior of the receptacle formed by the cylinder 15 is placed asuitable uantity of carbonaceous fuel 40, preferab y in granular form.

The applicator comprising the cylinder 15, the plates 17, 18 andassociated parts, is shown in position in connection with a melting pot50. In the example illustrated a quantity of metal 51 is placed in thepot to be melted by heat. The a plicator may be similarly inserted intoany ody of liquid for quick heating thereof. Furthermore, the applicatormay be employed for heating a room. By providing a path of escape fromthe upper portion of the interior of the cylinder 15 to suitableconducting passages, the products of combustion and unconsumed vaporsmay be carried to utilities spaced from the applicator. Such use doesnot prevent the use of the applicator for the direct application of heatas well.

In operation, the source of current 34 is started and its circuit closedto cause current to flow through the circuit of the electrodes 20 and21; the circuit also includes that portion of the carbonaceous fuelbetween the electrodes. On account of the high resistance of theelectrodes when cold little or no current flows. The valve 36 is set inthe position shown in Fig. 1. A supply of hot gas or vapor such assuperheated steam, for example, is now supplied through.

the passages 31 and the interior passage of each of the electrodes tothe lower extremities thereof. The heat of the vapor isimparted to theelectrodes whose resistance is reduced thereby, and current flows. Thetemperature of the incoming gases may be and generally is suflicientlyhigh to initiate combustion of the fuel surrounding the ends of theelectrodes. I

The heat obtained from the burning fuel also lessens the resistance ofthe electrodes and as the temperature rises a gaseous path fromelectrode to electrode results which has the characteristics of astable, enclosed arc.

The current flowing between the electrodes produces an intense heat. Apeculiar action now takes place, the theoretical explanation of which isin some doubt on account of obvious difficulties of observation; but itis thought that the action may be that the oxide of magnesia of whichthe electrodes are formed is decomposed, and

.almost immediately recombines, so that there is substantially no realor permanent combustion thereof. While in its decomposed state, however,it forms, in combination with the vapor emitted by the e-lcc' trodeends. or in combination with the fuel, a gaseous conducting path for thecurrent, so that a greatly extended gaseous resistor can be formed withconstant voltage and current factors. having the characteristics of anelectric arc.

The electrodes may be adjustedto var the distance between them. With thespecific adjusting mechanism shown, this can be done readily as soon asthe fuel surrounding them has been partially consumed.

The heat is imparted to the carbonaceous fuel 40 within the receptacle.The fuel is heated to a temperature of incandescence. The incoming vaporis dissociated by the intense heat produced and thus an initial supplyof oxygen at a high temperature is provided for combustion of the fuel.The combustion of the fuel and the current flowing between theelectrodes cooperate to produce exceedingly high temperatures, and it ispossible to obtain a temperature very high with respect to thetheoretical temperature of combustion of the fuel.

The heat transmitted by conduction through the electrodes 20, 21, totheir respective supports is imparted to the incoming stream of vapor.The vapor, although hot, is at a temperature considerably below themelting point of nickel chromium or other material of which the supportsare made, and serves to limit the rise of temperature therein andprevent damage thereto.

During the early period of the operation, the vapor after serving itspurpose, or the residue of the vapor escapes through leaks or crevicesin the devices. Later the valve -36 may be shifted to interconnectpassages 37 and 38 thus permitting circulation of the vapor in throughone electrode and out through another.

In the modified form of electrode terminal shown in Fig. 4, the splitcollar 30 is fitted over the upper end of the respective electrode, thefit being sutliciently tight so that the collar is securely maintainedthereon. The upper end portion of the electrode 20 may in this case bemade solid, thus forming a conductor for the electric current. Thisportion 20 above the hollow interior chamber of the electrode proper,may be made of a differently characterized material, such as carbon. Thelower portion of the electrode 20, and the transverse passage 31 leadingto the hollow interior thereof is formed of the same material as and issimilar in construction to, the corresponding portion of the embodimentof Fig. 3. Thus I have provided an electric fire pot in which anincreased rate of utilization of the heat energy, usually expressed inBritish thermal units, contained in a given charge or mass of fuel isobtained, and which is compact in construction and simple in operation.

Illustrative apparatus has been described but it is expressly understoodthat the scope of the invenion is not to be limited thereby, referencebeing had to the appended claims for that purpose.

What I claim is:-

1. A fire pot having an outer radiating y surface and arranged tocontain fuel, means for causing at least a portion of the fuel toincandesce, comprising electrodes extending into the fuel, and means forsupplying an oxygen carrying medium through the electrodes to sustaincombustion of the fuel.

2. A fire pot having an outer radiating surface and arranged to containfuel, means comprising electrodes for incandescing at least a portion ofthe fuel, and means for supplying an oxygen carrying medium to the fuelto sustain combustion thereof.

3. A fire pot. having an outer radiating surface and arranged to containfuel, electrodes extending into the fuel, and means for supplying a hotoxygen carrying medium to the electrodes to heat the electrodes and tosupply oxygen to the fuel.

4. A fire pot arranged to contain fu l, a. plurality of hollowelectrodes which are conductors of electricity only when hot, extendinginto the fuel, and means for supplying a hot oxygen carrying medium tothe electrodes to heat the electrodes and to supply oxygen to the fuel.

5. A fire pot arranged to contain fuel, electrodes extending into thefuel, and means for supplying an oxygen carrying medium to theelectrodes and to the fuel at a temperature above the ignition point ofthe fuel to heat the electrodes, to initiate combustion of the fuel andto sustain the combustion thereof.

6. A fire pot arranged to contain fuel, a plurality of hollow electrodesextending into the fuel. and means for supplying an oxygen carryingmedium through the electrodes to the fuel at a temperature above theignition point of the fuel to heat the electrodes. to initiatecombustion of the fuel and to sustain the combustion thereof.

7. A fire pot arranged to contain fuel, hollow electrodes which arenon-conductors of electricity at ordinary temperatures and conductors ofelectricity when hot. extending into the fuel, and means for supplyingan oxygen carrying medium through the electrodes to the fuel at atemperature above the ignition point of the fuel to heat the electrodes,to initiate combustion of the fuel and to sustain the combustionthereof.

8. A fire pot arranged to contain fuel, means for causing at least aportion of the fuel to incandesce, comprising magnesia electrodes, meansfor supplying electric current to the electrodes, and means forsupplying a hot oxygen carrying medium to the electrodes to heat theelectrodes to render them electrical conductors and to the trodes andthroughthe fuel, said electrodes being formed of material substantiallychemically inert with respect to the fuel at incandescent temperatures.

10. A fire pot arranged to contain fuel through the electrodes into thefuel and means for passing a current of electricit between saidelectrodes through said fue 16. A plurality of electrodes, a mass offuel surrounding said electrodes, a source of electric energyoperatively connected with said electrodes, and means for introducing aflow of vapor for providing) a gaseous path of electric conductivityetween the electrodes.

I 17. A heater comprising a casing having an outer radiating surface andforming a substantially closed; space arranged to conand means forcausing a portion of the tain a massof fuel,.and electrodes extending toincandesce comprising spaced electrodes mto the fuel, said electrodesbeing non-conextending into the fuel, and means for causing electriccurrent to .flow between the electhe fuel having a carbonaceous chemicalCOIIIPOSltlOIl and means for incandescing attrodes and through the fuel,said electrodes being formed of an oxide of magnesia.

11. A fire pot arranged to contain fuel,

least a ortion of the fuel including spaced electro es ofnon-carbonaceous material.

12. A fire pot arranged to contain fuel having a carbonaceous chemicalcomposition, means for incandescing at least a portion of the fuelincluding spaced electrodes of non-carbonaceous material, and means forsupplying an oxygen c'arrying'medium to the fuel.

' 13. A fire pot, a plurality of hollow electrodes which are conductorsof electricity only when hot, positioned therein, means for supportingthe electrodes whereby they may be relatively adjusted, means forsupplying a hot oxygen carryin vapor to the electrodes to heat theelectro es and to supply the oxygen in the fire pot, and means forsupplying electric current to'the electrodes.

14. A plurality of hollow electrodes which are non-conductors ofelectricity at ordinary temperatures and conductors of electricity whenhot, means for passing a hot vapor through the electrodes, a mass offuel surrounding said electrodes and means for passing a current ofelectricity betweeen said electrodes through said fuel to cause incan;descence of the fuel. 1

15. A plurality of hollow electrodes which are non-conductors ofelectricity at ordinary temperatures and conductors of electricity whenhot, a mass of fuel surrounding said electrodes, means for passing a hotvapor ductors of electricity at ordinary temperatures and conductors ofelectricity when hot.

18. A heater comprising a structure forming a substantially closed spacearranged to contain a mass of fuel, electrodes'which are non-conductorsof electricity at ordinary temperatures, and conductors of electricitywhen hot, said electrodes being positioned to extend into the fuel, andmeans for heating the electrodes. I

19. A heater comprising a structure forming a substantially. enclosedspace arranged to contain a mass of fuel, electrodes extending into thefuel and means for passing a vapor having a predetermined temperatureinto the fuel for controlling combustion thereof.

20. A heater comprising a container for fuel having an outer radiatingsurface, electrodes extending into the container, a source of electriccurrent operatively connected with the electrodes and means for passinga heatedvapor into the fuel whereby heat is generated by the combinedaction of the electric current, the heated vapor and the combustion ofthe fuel.

21. A heater comprising a container for fuel having an outer radiatingsurface, a plurality of hollow electrodes extending into the fuel, asource of electric currentopera tively connected with the electrodes and

